Equity - Schedule of Other Common Stock Activities (Details) - Common Stock - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Dividend Reinvestment and Stock Purchase Plan (in shares)	237	983	2,021
Conversion of DownREIT units (in shares)	3	78	145
Exercise of stock options (in shares)	120	32	133
Vesting of restricted stock units (in shares)	401	419	529
Repurchase of common stock (in shares)	141	157	237